Power-unit relay switch



y 14, 1929- P. E.-EDELMAN 1, 12,916

POWER-UNIT RELAY SWITCH Filed NOV. 25, 1927 IN VEN TOR.

Patented May .14,- 1929- UNITED STATES rnnrrr E. EDELMAN, or CHICAGO, rumors, assrenon r0 Ernnam rename, or

" CHICAGO, ILLINOIS.

POWER-UNIT REL Y SWITCH.

Application filed November.25, 1927. Serial No. 285,613.

present invention relates to an automatic switch for operating electrical de vic es and more particularly is suited for the automatic Operation from a radio receiving set filament control switch of a power supply unit which contains no battery such for example as a battery eliminator of the class disclosed in my pendin application for United States Letters 163,734, filed Jan. 26, 1927. An object is to start and stop thepower flow to the power unit when the radio set switch is turned on and off so that no electric current is consumed in the power unit when the radio set is not in use. A further object is to accomplish this by means of a relay switch which requires no change in the wiring of thepower unit itself but can be external- 1y attached thereto ifso desired. Other objects will presently appear.

I attain these objects by means of a relay switchand circuit therefor, of which a suitable example is shown in the accompanying drawing, in which,'Figure l is a diagram showing the relay switch and its circuits, and Figure 2 is a side view of the iron core 24 and shade ring 27 projected therefrom.

My relay switch starts operating on alternating current obtained from a small bell ringing transformer, 14 and continues its operation by means of the direct current supplied immediately by the power unit 1,

whereupon the transformer 14 is disconnected during the use of power unit 1 and causes no ripple current to reach output terminals 5 and 6. p

The power unit 1 may be of any type ems ploying no battery and has the usual output terminals 2,3 and input plug 4. The relay switch I provide can attach to input plug 4 and output terminals 2, 3, without disturbing unit 1.

'A'socket 10 attached to an alternatingcurrent lighting main supplies the primary power, and the plug connector 11 serves to connect the ,unit 1 and the relay switch to this source of power 10. Wires 12, and

, 13 connect as shown via either socket 7 or primary winding 15 of transformer 14,'according to the position of switch arm 40. When relay coil-.47 is not energized, switch arm 40 causes contact 49 to remain closed against contact 48 so that current flows via spring 44, wire 20 and primary coil 15 to fiatent Serial No.

cont-act 50 with contact 51,thereby discon- "necting primary coil 15 and causing current to flow via spring 43, wire 8, and socket 7, connecting to wire 13 via wire 9, and energizing power unit 1 connected at socket 7. Thus, either coil 15 will be energized while powerunit '1 is not, or vice versa. C011 15 of transformer 14 however consumes negligible current because secondary coil 16 is normally not supplying current except the momentary amount required to initially energize coil '47 when a load is first connected to terminals 5 and 6. Switch arm 40 has sufficient return force to restore contact 49 closed against contact 48 when coil 47 is not carrying current.

Secondary coil 16 0ftransformer 14 connects to relay coil 47 via wire 18 and also connects via wire 17 to spring 41 carrying contact 55. Switch arm 39 carries contact 54 normally open from contact 55.

Switch arm 39 connects via wire 21 to coil 16 of transformer 14. Contact 53 carried by switch arm 39 normally is closed to contact 52 carried by spring 42. Spring 42 connects via wire 56vto wire 58 and to negative output terminal 5 and negative terminal 2 of power unit lvia wire 58. Contacts 53 and 52 thus closed, normally short circuit the output terminals 2, 3, of power unit 1 so that the tendency of alternating current to flow back thru unit 1 from secondary winding 16 of transformer 14 is negligible. But

a circuit is provided to energize coil 47 from coil 16 via said shunt contacts 54 and 55 and permitting currentto flow via wires 57 and 58 from unit 1 thru coil 47- to the load ap plied to terminals 5 and 6. All tendency toward ripple current in the load applied to terminals 5 and 6 from transformer 14 is thereby avoided while the resistance inherent in winding 16 of transformer 14 is thru coil 47, switch arm 39 again closes contact 53v against contact 52. The closing of contacts 54 and thus short circuits winding 16via wires 17 and 21.

Coil 47 connects via wire 19 to output terminal 6. Coil 47 also has a portion of its turns short circuited at all times by wire'46. This is done to cause a certain timelag in the operation of the switch arms 39 and 40, and also to reduce the impedance of coil 47 to alternating current which flows therethru from transformer 14, so that a greater pull is obtained on armature 30 when coil 47 is'energized with alternating current.

When coil 47 .is energized, it magnetizes iron core 24 and causes armature 30 to be pulled toward core 24. The flow of alternating current thru coil 47 tends to make this pull on armature 30 unsteady as the distance between armature 30 and core 24 is reduced, so I introduce at one end of core 24, a heavy ring 27 or shade ring. This ring 27 in effect becomes a short circuited secondary winding when coil 47 is energized by alternating current and sets up a fiux at a ortion of core 24. at the end thereof WhlCh remains during the brief time that the flux setup thru core 24 b winding 47 is passing thru zero value. his tends to steady the pull on armature 30 sufiiciently. for satisfactory operation. The end view of core 24 shown in Figure 2 illustrates a suitable position for the ring 27.

Ring 27 is carried in a-slot 29in one end of core 24 and insulated therefrom by insulation 28. Ring 27 has no detrimental effect to the operation ofv coil 47 on direct current su plied from unit 1 via wires 57 and 58. .Q attering of armature 30 is thereby avoided and undesired sparking at contacts 48, 49, 50, 51, also 52, 53 and 54,55 is minimized.

Core 24 of relay switch 23- has a yoke 25 fastened thereto at 26. Yoke 25 supports an insulating mounting 45 which carries springs 41, 42, 43, 44 and switch arms 39 and 40 insulated from each other at this support.

Switch arm 39-carries an insulator pin 38 positioned adjacent to an insulator pin 37 attached to switch arm 40. Switch arm 40 also carries an insulator pin 36 adjacent to insulator in 35 which is fastened to-arm 31 comprise witharmature 30. A projection 34 on arm 31 limits the return travel of arm 31 under the. return force of switch arms 39 and 40. A pivot or shaft mounting 32 is supported from yoke 25 by support 33 and permits. arm 31 to move under the control'of the pull on armature 30 by core 24, or the return force from switch arms 39 and 40 which is made sufficient for the purpose to restore projection 34 against nating current from winding 16 passesv thru coil 47 thru the load circuit attached to terminals 5 and 6 sufiicient to pull armature 30 towards core 24. The impedance of power unit 1 does not prevent this pull because Wires 57 and 58 are at the start short circuited via contacts 53 and 52. The first pull on armature 30 however energizes power unit 1 and oper'atively permits current to flow thru coil 47 via wires 57 and 58 to maintain the operation as long as a load circuit is attached to terminals 5 and 6.

There is accordingly only a brie f period during which alternating current can flow at terminals 5 and 6 and this period is so brief that no hum will be heard in the re producer of the radio set connected to terminals 5 and 6. Relay 23 thus starts on alternating current but operates thereafter on the current supplied from unit 1 which is caused to receive energizing current via plug 4 under control of the relay 23. The load circuit attached to terminals 5 and 6 thus controls the operation of relay 23 so that no energizing current flows thru power unit -1 from socket 7 except when power unit 1 is supnlyingload current via termi nals 5 and 6.

The invention thus resides in the new and useful combination of elements producing the new result sought for, which is thereby attained in ractical and useful manner without requiring the use of any battery current or rectified current for starting and without introducing undesired ripple current in the load circuit attached to .terminals 5 and 6. -Various changes and modifications may be made without departure from the invention set forth and within the scope of the appended claims.

1. A power unit relay switch including an actuating coil electromagnet, means to start the {operation of said switch on alternatienlg current supply, means to reduce the imp ance' of said coil to the flow of alternating current therethru, means to maintain the operation of said coil by direct current flowing therethru,'and means to retard the magnetic pull of said coil electromagnet during the transfer of the operation thereof from alternating current to direct current.

2. A power unit relay switch including yoke 25 when coil 47 is not energized. terminals attachable to the input and outno arraaie put terminals of a power unit, a starting power supply for said relay switch, switch contacts operated by said relay switch and permitting power to flow from said power 'said switch contacts during the time that operati0n thereof is transferred from the starting power supply to the maintaining power flow from said-power unit. w

3. A power unit relay switch comprising terminalsattachable to a radio power sup-' ply unit at the input and output terminals of said unit, a separate starting power supply to actuate said switch, means to continue the operation of said switch on power-obtained from said power supply unit, and contacts controlled by said switch todisconnect saidstarting power supply therefrom when said power supply unit is operated by said switch. a

4. A power unit relay switch consisting of input and output feeders for a power unit, a transformer tocstart the operation of said switch, contacts controlled by said switch to short circuit saidoutput feeders during the instant that said transformer is actuating saidswitch, cooperating contacts controlled by said switch to transfer the continued operation of said switch on power obtained from said power unit, and. contacts to by-pass said transformer so that no energy flows therefrom to said output feeders when said power unit is operated. 5. A power unit relay switch consisting of an electromagnet having some of its coil turns short circuited, an armature pulled by said electromagnetfla transformer to start the pull of said electromagnet, means to steady said starting pull, a sequence of switch contacts actuated by the pullon said armature, and circuits controlled by said switch contacts'to operate a power supply unit and maintain the operation thereof from )power'obtained-from said supply unit.

6. power supply unit relay switch consisting of an electromagnet, an armature actuated thereby, a sequence of contacts oper- 'ated by said armature, a starting transformer to energize said electromagnet, a power unit energized under control of said contacts, means to transfer the operation of render said transformer inoperative while said electromagnet from said transformer to said power unit, and means to transfer said transformer out of service while the operation of said electromagnet is accomplished by said power unit.

7. A power supply unit relay switch con- 6 s'isting of input and output feeders for a power unit, an electromagnet, a separate transformer to actuate said electromagnet, an armature pulled by said electromagnet, a sequence of contacts controlled by the pull 6 on said armature, and circuits included by and connecting to said contacts to feed energy to said power unit, and todisconnect said transformer from said electromagnet when said power unit is energized. 7

' A power supply relay switch consisting of a double pole double throw switch including contacts controlled by 'an electromagnet, a transformer and a power unit alternately operated according to the position of one pole of said switch, and connections to the other pole of-said switch to short cir- 'cuit theoutput terminals of said power unit while said transformer is energized andto 8 said power unit is energized whereby said electromagnet is operated either by said transformer or said power unit according to the position of said switch, and means to maintain magnetic flux in said electromagnet during the transfer of the operation thereof from said transformer to said power unit.

9. A power supply relay switch attachable to a power unit consisting of an 1nput a socket and an output terminal connector for said power unit, an -electromagnet, a transformer to actuate said electromagnet, switch contacts operated by said electromagnet, and connections to said contacts to supply energy to said input socket when a load circuit is connected to said output terminal connector and to cut off the energy input at said input socket when said loadcircuit is disconnected from terminal connector, and means to cut off the operation of said transformer during the time that said load circuit is operated by said power unit.

In witness whereof I have hereunto set my hand and seal this 20th day of Novem- 1 bar, 1927.

PHILIP E. EDELMAN. [13.8.] 

